This invention relates to telephones.
It is known for telephones to have a base fitted with a keyboard or a disk for dialling call numbers and with a number of control knobs, and to have two handsets which may be placed on the base.
There are now also telephones having a single handset and whose base is so designed that it can be used as a second handset.
More generally, these telephones are either intended to be connected to the end of a single telephone line or intended to be connected to two lines or more.
The problem now is that each telephone is specifically designed to be connected to a set number of lines and to no other.
Thus, for instance, he who has a private telephone for two lines and moves into accommodation with only one available line, ends up with a useless telephone and must get another, which is of course a nuisance.